<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        .container {
            width: 100px;
            height: 100px;
            outline: 1px solid red;
            margin: 1px;
            /* background-color: blue; */
        }
        .container div {
            height: 100px;
            line-height: 100px;
            text-align: center;
            width: 100%;
            /* background: #88a86e; */
        }

    </style>
</head>
<body>
    
    <div style="display: flex; flex-direction: column;">
        <div class="container">
            <div>1</div>
        </div>
        <div class="container" style="outline-color: blueviolet;">
            <div>1</div>
        </div>
    </div>

</body>
</html>